Engine starting mechanism



H. BAER ENGINE START ING MECHANISM Filed April l, 193'? INVENToR. Howard aef' NEY.

Patented Dec. 27, 1938 Howard Baer, Jersey City, N. J., assignor to Eclipse Aviation Corporation,

East Orange,

N. J., a corporation of New Jersey I Application April 1, 1937, Serial No. 134,409

This invention relates to sta internal combustion engines.

13 Claims.

rting devices for Onel of the objects of the invention is to provide `an engine starter of the torque applying type embodying novel means for producing engagement with and transmission of torque to a membe of the engine to be started.

A further object of the invention is to provide in a starting device of the foregoing character, novel means for converting an axially directed pressure into a rotation producing force whereby the axial movement of the driving member is translated to the engine cranking member.

A further object of the invention is to provide a novel starting mechanism of the type employing a plurality of power actuated pistons one of which operates to produce engagementbetween the starting mechanism and a member of the.

engine to be started,` and the operates to impart a crankin engine engaging member.

other of which g torque to the Another object of the invention is to provide a multiple power member 'starter of the foregoing character which makes it possible, by the use of a novel construction, to obtain a quicker and more certain inter-engagement between the teeth of the engine engaging member and the engaged member of the engine, prior to any appreciable axial movement of t he larger of the two power actuated pistons above referred to. Other objects and advantages tobe derived from the use of the invention reside in the specific construction, combina tion and relation of parts whereby a compact, eiiicient and easily operated and maintained unit is produced, all of which objects and advantages will appear more clearly upon an inspection of the following specification, with reference to the accompanying drawing illustrating the preferred embodiment of the invention.

It is to be expressly understood however, that the said drawing is for the purpose of illus is not tration only and to be construed as a' definition of' the limits of the invention, reference being had to the appended claims for this purpose.

In the drawing, wherein like reference char-v acters refer to like parts throughout the severalrviews:-

Fig. 1 is a longitudinal axial section through a device embodying the invcntion;

ig. 2 is a slightly enlarged of the valve member;

perspective view Fig. 3 is an enlarged transverse sectional view taken along line 3-3 of Fig. 1;

interparticularly to Fig. 1, the piston actuated unit is contained within a sectional housing including cylindrical parts I'I and I0, the latter having a flange I2 by which it is secured to the engine 10 crankcase I3 as by bolts I4, the ange being conveniently of a size standardized for aircraft engine starters. The engine crankshaft, 'or other drive shaft (not shown) is provided with a clutch element II engageable by the piston actuated 15 clutch element I5 as will be later more fully described.

Cylinder I1 has a head end I8 and a crank end 20, the latter being shown as an integral part of an internally splined tube 2I. -Sli'dably fitted 20 Within the cylinder I1 is a piston 23 movable with a hollow screw 24 which is externally splined as at 25, to cooperate with the internally splined tube 2 I. Between the cooperating grooves 25 and 26 are placed a series of friction reducing 25 members shown as balls `2l assembled in a cylindrical cage 30, suitable stops 28 and 28a being provided at each end of the splined grooves to hold the cage 30 against more than predetermined endwise movement. A second screw 22 30 is drivably connected with the screw 24 by helical grooves or threads 29and.3I which permit the axial travel of the piston 23 but cause rotation of the screw 22 because of friction reducing balls 36 assembled in cage 35 and inserted in the 35 helical grooves 29 and 3|, stops 28o. and 23h likewise serving to limit the endwisel movement of the cage. An anti-friction thrust bearing 32 is preferably interposed between a flanged skirt 34 on the rear end of al spacer member 34h and 4g an inwardly extending circular portion 33 of the body I0, the said bearing 32 acting to take the axial thrust to which the inwardly extending rim 34a,'on the forward end of the spacer member, is subjected when engaged by the forwardly 45 moving iiange of head member I9. A spring 31 has one end resting against the closure plate 20 of the cylinder I1, and itsopposite end abuts the thrust ring 38, which is, in effect, the-outer race 38 of a ball-bearing assembly 40 axially movable 5g with' but rotatably free of the piston 23, the inter- Due to the bolted split damp connection 4|y between the cylinder I1 and the body flange I6,

the former may be quickly detached for remov- `ing any fouling that may occur where combustible cartridges are used as the source of fluid pressure to move the piston 23.

The present invention, as above indicated, includes improved means for automatically controlling both the meshing of parts I5 and II, and the exhaust of the iiuid pressure from the cylinder upon completion of the cranking operation. This combined meshing and exhaust control may be effected by providing a path along which the pressure iiuid may ow to act directly and immediately upon the head portion I9 of the sleeve 22 whereby said sleeve 22 may move axially forward prior to and independently ofthe beginning of axial movement of the main piston 23 as is explained` more fully here-in-after-the said head portion I9 of the sleeve 22 thus constituting, in iect, a separate piston with exposed surface area greater than' the initial exposed surface areas of the piston 23 and parts integrated therewith-the annular boss 9| of the cylinder head serving to block oil the major portion of the piston area with the parts in the relative positions shown in the drawing. Forward movement of piston I9 tends to'compress the spring 41, to transmit, by way of said spring, a. forward meshing movement to the clutch member` I5, thereby bringing the latter into operative engagement with the engine member I I. As shown, the pressure fluid path leading to the piston I9 includes openings formed by cutting away the flanged forward end 1U of the exhaust valve 42 to form :fingers 10 as indicated best in Fig. 2, whereby the uid entering through chamber 56 may instantly pass directly into a long annular chamber between the rod 46 and the tube 1I, which constitutes a centrally disposed extension of the piston 23, to which piston the flanged rear end of the tube 1I is connected by suitable screws 12 or equivalent means, as illustrated; the forward end of the annular chamber thus formed having communication with the bore of the sleeve 22 by virtue of I.

recesses 52a formed in the nut 52 inserted on the forward end of the rod 46 and best viewed in Fig. 4, and also by virtue of the passage-way through the thickened forward portion 14 of the 'tube 1I. This forward portion 1-'4 is provided with sealing rings 16 which prevent seepage of fluid or particles contained therein backwardly into the space surrounding the tube 1I, while at the same time facilitating and. permitting free sliding movement of the tube within the bore of sleeve 22 as the piston 23 moves forward in the cylinder I1. The valve 42 is carried by the rod 46 and is of such a length that with the parts in the positions indicated in Fig. 1, a spring 49 will bear against the nut 52 on the rod 46 to hold said valve 42 on the seat formed in the head 44. At the commencement of an operative cycle of the motor, such as is occasioned by the delivery of fiuid pressure to the chamber 56, this fluid pressure will assist the spring 49 in maintaining the exhaust valve 42 closed; but as the piston nearly reaches the end of its movement, a collar 53 extending inwardly of piston 23 will be brought into engagement with the movement of the vpermits constant clearance 'between the said collar 53 and the rod 46 (as shown clearly in both Figs. 1 and 3) whereby the pressure fluid is always free to pass between the chamber 56 and the bore of sleeve 22passage being first from chamber 56 to the bore 22 (at the beginning of the cycle of operations) and subsequently in the reverse direction to allow the pressure fluid to be exhausted in response to the opening of the exhaust valve 42-that is, its removal from its seat in the housing 44-by the engagement of the collar 53 with the nut 52 at the end of the stroke of the piston 23 as above described. The exhaust valve having been thus unseated, the spring 48 will be effective for holding it in open position, its maximum opening movement being limited by a longitudinally slotted cylindrical stop 54 having a Aflange 66 abutting the end-surfaces of Vthe fingers 61, formed by longitudinally slotting the neck portion 56 of the head end I8. This neck 56 is externally threaded, as shown at 68, to receive the housing 44, the latter being screwed upon the threads 68 until surface 69 of the housing 44 abutsthe flange 66 of the stop 54 and with the inlet passage aligned with the longitudinal slots 61a between fingers 61. Stop 54 is adapted to be nrst slipped over the valve-head 42; and due to the eccentricity of the apertured portion of the said stop, the said aperture has suiicient surface remaining to constitute a stop or abutment 54a for valve head 42 in the open position of the latter, while at the same time being aper- .tured sufficiently to permit insertion and withdrawal over said valve head.

against, the fingers 10 at the end of valve stem 42v for again seating the valve, as shown in Fig. 3. This insures closing movement of the valve at the'time the piston has substantially completed its return movement, the closing being initiated and assisted by the action of the spring vmeans 49 above described. It is thus apparent that the exhaust means is of such construction as to remain open during the major portion of the return stroke of the piston so as to insure substantially complete scavenging. In order to permit sleeve 22-for the purpose of meshing the parts I5 and II independently of the movement of the piston 23-without at tloe same time creating too severe an axial thrust on the driving sleeve 24 with which the said sleeve 22 is threadedly engaged, the ball-cage assembly 35 is preferably of a length somewhat less than the distance between retainer rings 28D and 28a whereby forward movement ofthe sleeve 22 to the extent necessary to induce complete mesh between parts I5 and II occurs pri-or to taking up of the thread-clearance between the end-balls 36 lmoving means, there being only'a portion of the described, such continued forward movement of ,relative axial movement.

the piston I9 being possible because of the clearance between the forward end of thesaid piston and the jaw I5' to which the forward end is splined as indicated Aat 88, the springy 41 also being suiiiciently vcompressibleI topermit such axialmovement a certain amount of rotary move-y ment reverse to the rotary movement of the cranking will also occur due to the eifect of the stationary threads of the outer sleeve 24 upon those of the sleeve 22 and such rotary movement will therefore relieve the condition of cornered tooth contact, whereupon spring 41 will expand from its compressed condition and thereby press the jaw member .l5,into full engagement with the engine member Il.

What is claimed iszl. In an engine starter the combination with a piston adapted for axial advance, helical means associated with the piston lto produce-rotary motion from said advance, an engine engagingl member rotatable by said rotary motion, and means for moving said engine engaging member longitudinally but independently of said piston, said last named means and said piston beingv disposed so that the actuating fluid first-acts upon said moving means and exerts engagement maintaining pressure thereupon during the entire axial advance of the piston, there being only a portion Iof the normal operatingr surface of the piston exposed to` said actuating `fluid at the beginning of theengine engagingoperation.

2. In an engine starter-the combination, with a housing, of a piston adapted for axial advance within said housing, helical means associated with the piston to produce rotary motionfroml ing said engine engaging member longitudinally l but independently of said piston, said last named means and said piston being disposed so that the actuating fluid rst acts upon said moving means and exerts engagement maintaining pressure thereupon during the entire axial advance of the piston, there being only a portion of the normal operatingsurface of the piston exposed to said actuating fluid at the'beginningV of the engine engaging operation, and means integral with said piston housing for initially closing off the remaining portion of the'normal operating surface of said piston from the path of the actuating' fiuidv which is acting upon said moving means to move the engine engaging member longitudinally independently of movement of said piston.

y3. In an engine starter the combination with a piston adapted for axial advance, helical means for moving said engine engaging member longitudinally but independently of said piston, said last named means and said piston being disposed so that the actuating fluid first acts upon said During this relative 4. In an engine starter the combination with a piston adapted for axial advance, a housing therefor, helical means associatedwith the piston to produce rotary motion from said advance,

' an engineengaging member rotatable by said rotary motion, means for moving said engine en- .g'aging member longitudinally but independently of said piston, said last named means and said piston being disposed so first acts upon said moving means and exerts engagement maintaining pressure thereupon during the entire axial advance of the piston, and means integral with said housing for confining the actuatingl uid `to contact with a portion only of the normal operating surfacev of said piston, at the beginning of the engine engaging operation.

5. In an engine starter the combination with a piston adapted for axial advance, a housing therefor, helical means associated with the piston to produce rotary motion from said advance, an engine engaging member rotatable by said rotary motion, means including a second piston for moving said engine engaging member longitudinally but independentlyl ofl said piston, said two pistons being disposed so that the actuating fluid first acts upon said moving means, and means integral with ,said housing for confining the vactuating iiuidto contact with a portion only of ing operation, said -portion having an effective pressure area less than that of said second piston.

6. In an engine starter the combination'with a piston adapted for axial advance. a housing therefor, helical means associated with the piston to produce rotary motion from said advance, an engine engaging member rotatable by said rotary motion, means forfmoving said .engine engaging member longitudinally but independently of said piston, vsaidlast named means and said piston being disposed so that the actuating fluid first acts upon said moving means, said moving means including a second piston located between said first named piston and said engine engaging member and further acting as a part `of the driving connection for translating the axial movement 'of said first named piston into a rotary cranking movement of said engine engaging member, and means integral with said housing for confining the actuating fluid to contact with a portion only of the normal operating surface 4of said first-named piston, at the beginning of the engine engaging operation, said portion having-'an Y effective pressure area less than ond piston.

7. The c'ombination with a rotatable engine engaging member and a non-rotatable 'driving member, of a piston for moving said driving member forward, a housing for said piston through which iiuid enters to drive said piston and driving member forward, a valve controlling exhaust of the uid, and means on said piston for actuating said valve, said means including a part apertured to permit the actuating fluid to that of said secling the lld that first act upon said engine engaging member prior to contact with the major part of the plstons working surface.

8. The combination with a rotatable engine engaging member and a non-rotatable driving member, of a piston for moving said driving member forward, a housing for said piston through which fluid enters to drive said piston and driving member forward, and means including a second piston forA driving said engine engaging member forward, said last-named means also including a part carried by said firstnamed piston for directing the fluid that first enters the housing into contact with said second' piston prior to contact of any of the uid with the major working surface of said rst-named piston.

9. 'I'he combination with a rotatable engine engaging member and a non-rotatable driving member, of a piston for moving said driving member forward,`a housing for said piston through whichv uid enters to drive said'piston'and driving member forward, means including a second piston for driving said engine engaging member forward, said last-named means also including a part carried by said first-named piston for directenters the housing into contact with said second piston prior to contact of any of the :duid with the'major working surface of said first-named piston, and means including a member rotatably surrounding said piston-carried part for translating the forward movement of said driving member into a rotary movement of said second piston and engine engaging member.-

10. The combination with `a rotatable engine engaging member and a non-rotatable driving member, of a forwardly moving piston for moving said driving member forward, a housing for said piston through which-uid enters to drive said piston and driving member forward, and means including a second forwardly moving piston for driving said engine engaging member forward, said last-named means also including a yieldable thrust-transmitting connection between said second piston and -said engineengaging member. A

-gine engaging memberl engagingmemberforward, said last-named means gine engaging member.

11. The combination with a rotatable engine engaging member and a non-rotatable driving member, of a piston for moving said driving member forward, a housing for said piston through which fluid enters to 'drive said piston and drivg -ing member forward, and means including a second piston having telescopic engagement with said engine engaging member for driving said engine engaging member forward, said last named means also including a part carried by said rst-named piston for directing the fluid that rst enters the housing into contact with said second piston prior to contact of any of the working surface of said first-named piston.

12. Thecombination lwith a rotatable engine uid with J the major engaging member and a non-rotatable driving v member. ofl al piston for moving said driving member forward, 'a housing 'for said piston through which fluid enters to drive said piston and driving member forward, means including a second piston having telescopic engagement with said enfor driving said engine 13. The combination with a rotatable engine engaging member andca non-rotatable driving" member, of a forwardly moving piston for lmoving said drivingmember forward, a housing for said piston through which uid enters to drive said piston-and driving member forward, and means including a. second forwardly moving piston having telescopic engagement with said engine engaging member for driving said engine engaging member forward, said last-named means also including a` yieldable thrust-transmitting connection between said second piston and Isaid engine engaging member. v

HOWARD BAER. 

